Drilling thermostat
 

AS OF 8-23-07
New Mishimoto all aluminum radiator
2 fans wired always on
160* thermostat, holes drilled, and now just completely removed
different coolant mixtures, and redline water wetter
new oem mitsu headgasket
new coolant line and clamp
new gaskets
new rad cap
vented hood
new water pump (better design then what was in there) and o-ring
burped numerous times




OK in my never ending quest to figure out what in the heck is going on with my car, I'm back to the thermostat again. My car runs hot mainly when driving on the freeways. Hot as in the needle starts to move past straight up and down and I get scared and stop. If I crank the heater, this helps quite a bit, but it sucks driving everywhere with the heater blasting.

So I've been reading up about how people drill little holes in their t-stat. Now I'm staring at mine, and the only spot there's any room to drill, is the big ring around the edge. But I don't see what that would do, that's not the part that moves up and down. Plus there's already a large opening in the top, where the rod connects to. Anyone able to clear this up for me at all?

BTW, car is a 91 tsi. Thermostat is a 160* one from AZ.

Other things I'm doing right now is replacing all the coolant. Going to go with a new mix of maybe like 65water/35antifreeze. Also dumping a bottle of water wetter in. It doesn't appear that I'm losing coolant, but sometimes I think I can smell some. But everytime I pop off the cap, it's full to the top, and the overflow doesn't seem to be budging at all.

Re: Drilling thermostat
 

Im assuming its a new Tstat. Drilling a whole in the tstat will let coolant flow through the engine even when the tstat is closed. So drilling into the metal ring will do what you are talking about.

Re: Drilling thermostat
 

I understand that drilling a hole is supposed to allow coolant to pass while it's closed. But I am staring at this thing, and I don't see how that is the case. There are 2 huge openings at the top of this. This ring never moves, nor does anything ever seem to seal up against it. So I don't understand.

Re: Drilling thermostat
 

Drill on the outside of those 2 openings on the silver/metal part.

If you are wondering how it opens/seals, go boil a pan of water and stick the T-stat in with a pair of pliers. You can watch it work...

Re: Drilling thermostat
 

I did just do that about an hour ago actually, because I was curious. But I mean, the center piece is what seemed to move, not the big metal ring around the edge. And still, there are those 2 huge openings in the center, so I don't see what my little holes are going to do because coolant could already go through the big openings in the center. But I'll quit trying to understand I suppose, and just go drill the dumb holes. Thanks!!!!

Re: Drilling thermostat
 

Have you pressure tested your radiator cap?

Re: Drilling thermostat
 

Brand new radiator cap.

I just noticed something. My drivers side fan is working intermittently. That is the one I've always had wired constantly on per RRE's reccomendation, because it sits right in front of the turbo and helps to blow the hot air away from the radiator. That was coming on and off quite a bit. Wiggling the wires would make it come on and off. Finally it just hard failed it looks like. Now I'm looking for a new slim fan. I hope this is it.

Re: Drilling thermostat
 

Brand new doesnt mean its good!

Re: Drilling thermostat
 

How do you pressure test a radiator cap? I don't even think my old cap was bad, but I replaced it anyway. And with the new one, the car acts the same way.

I did drill the holes, but they didn't do anything. I just got the new fan put in, so now we'll see if that helps at all. I sure hope so.

Re: Drilling thermostat
 

Do you have a fan on the passenger side? That fan takes most of the heat exchange in 1Gs because the inlet and outlet and both on the passenger side not in the middle and the majority of heat will be on the passenger side. put a fan on there.

Re: Drilling thermostat
 

What kind of shape is your radiator in? did someone before you put 14 bottles of stop leak in it and its keaping it from flowing properly? You try and just run it with no thermostat and see what temps you run?
I had a similar problem with my old grandam and the overflow radiator cap was bad and not venting and building pressure so it would constantly overheat.

Re: Drilling thermostat
 

OK I suppose I should have put more info on my car, so here it is:

New coolant in the car. Approximately a 85/15 water/coolant mixture, with a whole bottle of Water Wetter.

Brand new all aluminum mishimoto radiator.
http://www.carbon-fiber-products.com/MMRAD-ECL-90_2.jpg

Brand new cap.
http://www.dsmlink.com/forums/attach...5&d=1149023676

Brand new 160* thermostat, with two holes drilled in it now.

I don't seem to be losing any coolant, the overflow, and engine coolant levels don't seem to be budging really.

I have a 14" puller on the passenger side, and a 10" puller on the drivers side. The only thing that I don't like about the pass side one, is that the top sits flush on the fins, but the bottom is maybe 1/2" off the fins. But I've read about plenty of other people not having the fans 100% flush, and being fine. But maybe that is something I could look into. Also, both fans are wired ALWAYS ON. I used to have the 10" always on, and the 14 come on when it's needed. But ever since this issue, I've had it always on now too.

I'll also add that it did pretty well on a compression test, 165-170 across the board, and passed a leak down test at around like 120psi or so I believe.

Now, I just drove from Blaine, to Minnetonka, to Plymouth, and back to Blaine. The car is still running hot. If I have the heater on, it runs good though. But I did notice something that I guess I hadn't before, and it kind of makes sense of things a little more now. I like to explain everything so this might be a long paragraph, and full of obvious stuff, but just putting it out there.

As my EGT's go up, my coolant temp goes up. Before I was having a hard time wondering why on 45mph roads and at idle, my car would stay a good temp, but when either getting on the gas a little, or when on the highway, it would climb quite a bit. Typically in the past, if I had cooling issues, getting on the highway helped because of more airflow. Well I have a slightly thicker fmic then i used to, and the external fins are more dense as well. So what I'm getting at mainly is, it seams that the heat from my manifold, turbo, O2 housing, may be affecting my temps quite a bit. While cruising on the freeway, my EGT's are up in the 600's usually. When at a stop light they are drastically lower obviouslly. When cruising around on a 45-55 mph road, the egt's are also lower then on the freeway. I think I'm just not getting the airflow to the radiator that I used to, and that I need to. And the heat is just building up in the engine bay, and the radiator is catching a lot of that heat since all I have for heat shields is a JMF Stainless Steel one over the manifold. I think I need to find a way to get more flow to the radiator, or possibly put some vent holes in the hood to allow that heat to escape. I think that'll really help my situation.

I have DSMLink setup to turn on the CEL when the coolant temp reaches a certain level. When the CEL comes on, all I have to do is turn on the heater and it goes away in a minute or 2. If just driving around like 45-55 mph roads, and my egt's are quite lower, I can usually leave the heat off. But soon as those egt's get higher when I get onto a freeway, the temps rise, and I turn the heater on, and the temp stays pretty steady.

OK sorry for the long explanation, but if this works, and helps someone in the future, then yeehaw!

Re: Drilling thermostat
 

Question:

I want to go in and re-torque my head studs as well. When I go to retorque them, am I supposed to go to one nut, loosen it completely, then retorque it, and just do that one at a time? Starting from the middle and work my way out? I just ran across someone saying that about retorquing head studs, and wanted to see the general consensus here.

Re: Drilling thermostat
 

I re-torque them without loosening them.

as for the t-stat. remove it. All it does is keep your heater working.

-A. Swift

Re: Drilling thermostat
 

Swifty, you fail......

Re: Drilling thermostat
 

Your kidding right?
Joe

Re: Drilling thermostat
 

yes, I am kidding. I'd pressure check the system and figure out where all the coolant is going. Does your water pump work well? To check, pull off a heater hose of some sort, and start the car. If the coolant is GUSHING out, the pump is good. If it dribbles out, then try a new water pump.

-A. Swift

Re: Drilling thermostat
 

Once again, you fail..... :(

Re: Drilling thermostat
 

Try again LB. You stalking me now? How else would you check the water pump's pumping abilities, mr. smartass? I'm pretty sure that would give you an answer.

-A. Swift

Re: Drilling thermostat
 

I'll show you pumping abilities ;) On an on-topic note.... I dk, I don't hve one. time to get more crunky :)